1. Field of the Invention
This invention relates to the field of internal combustion engines. More particularly, the present invention comprises an internal combustion engine having a sliding guillotine valve.
2. Description of the Related Art
Most modern internal combustion engines operating on the Otto cycle (or close derivatives such as the Miller cycle) utilize intake and exhaust valves (1) to allow air to fill the combustion chamber during the intake stroke, (2) to trap air in the combustion chamber during the compression stroke and power stroke, and (3) to evacuate the products of combustion from the combustion chamber during the exhaust stroke. The timing, lift, and duration of valve opening is most commonly controlled by the rotation of a camshaft. The camshaft is mechanically linked to the output shaft of the engine such that each valve operates in synchronization with the engine's combustion cycle.
In order to change the timing or duration of valve opening, one must replace the existing camshaft with a camshaft having a different cam geometry (or utilize complex mechanisms to vary the distance between the camshaft center and the valve stems). Because engines are generally equipped with camshafts having nearly optimal cam geometries, this is not much of a concern in conventional vehicle applications. When one wishes to employ a more aggressive tuning (such as in racing applications) or when one wants to improve fuel economy, having the ability to vary the timing, lift, or duration of valve opening is desirable.
Optimal timing, lift, and duration are functions of engine speed and load. Thus, in order to operate at optimal volumetric efficiency, it is necessary to vary timing, lift, and duration throughout an engine's powerband. It has become increasingly common to utilize multiple intake or exhaust valves on a single combustion chamber or to utilize multiple camshafts or cams to control a single valve. These systems improve volumetric efficiency, but do so at the expense of additional weight, cost, and complexity. Thus, it would be desirable to provide an intake and exhaust valve design which is highly variable such that different timing, lift, and duration may be employed throughout the engine's powerband.